Just got a call from this company...Who are they?

It is a security company selling I think alarm systems. I notified them that we were on the do not call list and threatened a lawsuit, hopefully they will no longer call.

I tried calling back twice but it's busy.

I will keep trying, though not as eagerly and as often as they call here.

They called repeatedly, sometimes within 2 minutes of each other.  They will not leave a message and when I put them on hold to look for the owner (they ask for him by first name.  One lady attempted his last name but said it wrong, another just used the initial.), they hang up.

Same number has been calling all day and does not leave message.

Same number just called...twice in 10 minutes. Caller Id was Melissa Barker? Would not leave a message.

I have gotten 3 calls in the last 5 hours for this number and they will not take my number off their list.  They ask for a nonexistant person and won't take the number off unless they speak to that person (who doesn't exist)